package day07;

import java.util.Random;
import java.util.Scanner;

/*
* 需求：生成？为验证码（大写字母，小写字母，数字）
* */
public class verificationCode {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int a = scanner.nextInt();
        System.out.println(Generatecode(a));
    }
    /*生成验证码*/
    public static String Generatecode(int len){
        String code = "";
       char[] chs = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x',
               'y','z','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T',
               'U','V','W','X','Y','Z','1','2','3','4','5','6','7','8','9','0'};
        Random random = new Random();
       for (int i = 1;i<=len;i++){
           int index =random.nextInt(chs.length);
           code += chs[index];
       }
       return code;
    }
}
